Low molecular, homogeneous catalysts for polymerization have been suggested and used for the polymerization of many monomers to macromolecules. This is valid for radical, anionic and cationic catalysts and for organometallic mixed catalysts. Difficulties with homogeneous polymerization catalysts often occurs in connection with the separation of the catalyst and the polymer. As a result, the properties of the polymer are undesirably influenced or subsequent expensive separations become necessary.